Proportion of patients who have reach minimal manifestation state (according to MGFA criteria) and are not treated with prednisone after 12 months of treatment and have not relapsed during the next 3 months.

Cumulative dose of prednisone at twelve months

Proportion of patients having reached minimal manifestation state 12 months

Mean dose of steroid to maintain minimal manifestation(MM)[The dose of steroid should be decreased by the rate of 5mg/alternate day/ 4 weeks after the initiation of tacrolimus or placebo treatment as far as the MM state should be maintained.]